A moment we stared breathlessly at each other over the dead thing, then without speaking sprang to the wall, where Jor Dahat braced himself to repeat our former procedure. In a moment he had raised the Arcturian above him, and within another moment Sar Than was raising me likewise until I had again gained a grip on the rim of the shaft above. A fierce struggling effort and I had pulled myself up to the floor of the dim-lit corridor, where I lay panting for a moment, then leapt to my feet and over to the recess in the wall from which I had seen the flexible ladder taken. A moment I pawed frantically in the recess, then uttered a sob as my fingers encountered the cold metal of the ladder. It was but the work of an instant to lower it into the well for my two companions to climb up, and then we gazed tensely about us.
The long, dim-lit corridor was quite empty for the moment, though away down its length we glimpsed the square of white light that marked the point where it debouched into the great caverns. That was our path, we knew; so down the corridor we ran, between the rows of those shaft-cells on either side, until we were just passing between the last two of those shafts and were reaching the point where the corridor narrowed once more. And then we suddenly stopped short, stood motionless; for, not a hundred yards ahead, a double file of the nebula guards had suddenly issued from a door in the corridor's wall, and were gliding straight down its length toward us!
V
For a single moment death stared us in the face, and we stood there stupefied with terror. As yet the guards approaching us seemed not to have glimpsed us, owing to the corridor's dim light, but with every moment they were drawing nearer and it was but a matter of seconds before we would be seen and slain. Then, before we had recovered from our stupefaction, Sar Than had jerked us sidewise toward one of the last shaft-cells in the floor that we had just passed.
'Down here!' he cried, pointing into its dark depths. 'Down here until they pass!'
In a flash we saw that his idea was indeed our last chance, and at once lowered ourselves over the dark shaft's rim, hanging from its edge with hands gripped on that edge.
We had not been too soon; for a few seconds later there came the rustling sound of the guards passing above, gliding down the corridor past our place of concealment. As they glided by we hung in an agony of suspense, hoping against hope that they would not glimpse our hands on the pit's rim, or notice the absence of the creature left to guard us. There was a long, tense minute of waiting, and then they were past. We hung for a few moments longer, with aching muscles, then drew ourselves up to the corridor's floor once more and started down its length toward the square of white brilliance in the distance.
Down the dim-lit corridor we ran, past open doors in its walls through which we glimpsed great halls and branching passageways, all seeming for the moment deserted. A few moments later we had reached the corridor's end, and were peering out into the gigantic, white-lit space that lay beyond, a space alive and clamorous with the same multifarious activity as when we had come through it. To venture out into that great place of humming machines and thronging nebula-creatures was to court instant death, we knew, yet it must be crossed to gain the single shaft that led upward. Then, while we still hesitated, I uttered a whispered exclamation and pointed to something in the shadows beside us, something big and round that lay just inside the broad corridor's dusk, and that gleamed faintly in the dim light. In a moment we were beside it, and found it to be one of the great turtle- machines that swarmed across the floors of the vast caverns beyond us, though this one was unoccupied, its round door open to expose the hollow interior of the dome.
'There's our way out!' I cried. 'There's room in it for the three of us!'
Within another moment we were inside it, crouching together in the cramped space of the interior and swinging shut the little door. I found that a narrow slit running around the dome allowed us to look forth, and that a little circle of switches grouped around a single large lever were evidently its controls. Swiftly I pressed these switches in a series of combinations, and then there came a welcome hum of power from beneath and we were gliding smoothly out of the shadowy corridor into the full glare of the thronging, white-lit cavern, my hand on the central lever guiding our progress.
Tensely we crouched in our humming vehicle as it moved smoothly across the cavern, between the rows of great machines, toward the corridor opening in the opposite wall. The thronging nebula-creatures about us paid us no attention whatever, taking us for but one of the scores of turtle-machines that were busy about us. Hearts beating high with our success we glided on toward the dark wall-opening that was our goal. A score of feet from it we suddenly held our breath as another of the turtle-machines collided suddenly with our own, but in a moment it had glided away and in another moment we were again in the shadows of a dim-lit corridor, gliding down its length toward the shaft that led upward.
We reached the corridor's end, sprang out of our machine and through the door into the well-like bottom of the shaft. At once the plant-man was clambering up the peg-ladder, followed by the Arcturian with myself last. Up, up we climbed, putting all our strength into the effort, for we knew that not many minutes remained for action. Then suddenly as I looked down I stopped and breathed an exclamation; for standing at the bottom of the shaft were two of the nebula-creatures, not more than a hundred feet below us-two white masses of flesh that were staring up toward us.
A moment we hung motionless on the pegs, while the two weird beings gazed up, and then we saw one of them glide back into the corridor, racing back to the great caverns to sound the alarm, we knew. The other gazed up at us once more and then, to our horror, began to climb swiftly up after us.
I think now that of all that befell us there in the nebula world the moments that followed were the most agonizing. Swinging ourselves up by sheer muscular power, from peg to peg, we clambered up that giddy ladder, through a darkness impossible of description. Somewhere in that darkness below me, I knew, the nebula-creature that pursued us was swinging up after me, and I knew that to such a creature the negotiation of this dizzy ladder was child's play. Yet, spurred on by deadly fear, I struggled upward with superhuman speed, a hundred feet, another hundred, until a hope flashed across my brain that the thing that pursued us might have given up that pursuit. Then above us I glimpsed a little dot of glowing light, knew it for the shaft's mouth far above. And at the same moment that I glimpsed it, I felt a tug on my ankles, a powerful arm fasten round my body, and knew that the pursuing creature had reached me.
I cried out involuntarily as I felt my feet twitched off the pegs on which they had rested, and dangled for a moment there by my hands while the creature below me tightened his grip on my feet and began to pull me steadily downward. All his force he must have put into that effort, and I felt my hands slipping on the peg which they held, knew that once I lost my hand-grip the creature below would release my feet also and send me hurtling down to death on the shaft's floor far below. In a deathly silence I hung there, striving against that deadly pull, and then felt one of my hands torn from its grip, felt the fingers of the other slipping on the peg they held, felt my will relaxing-
Then someone had suddenly swung down past me from above, and I glanced down to glimpse in the dim light from above Sar Than, swinging swiftly down past me and hanging by one of his powerful limbs while with the other three he grasped the creature below me. Instantly the latter's grip on my feet relaxed, there was an instant of swift scuffling below me, and then I glimpsed the shapeless body of the nebula-creature forced from its hold on the pegs, hurtling down into the darkness to strike the floor far below with a smacking thud. The next instant Sar Than was up to me and was pulling me up until I again clung safely to the pegs. Only the Arcturian, with his four strange limbs, could ever have successfully battled the nebula-creature thus on that giddy ladder of pegs.
But now we were again clambering up, calling on all our strength to bear us on, watching the little circle of dim light above broadening as we climbed up toward it. Below us, we knew, the alarm had been given, and within a few minutes now a horde of the nebula-creatures would be rushing up the shaft. And but minutes were left for us to act in, so that we put every effort into a mad burst of speed that within a few more minutes had brought us up to the shaft's mouth.
Jor Dahat, above us, was the first to reach its level, and I saw the plant-man raise his head and peer cautiously forth, then beckon us upward. Silently, stealthily, we climbed up, crept over the shaft's edge until we
